Add back trailing whitespace removed on previous force push

CHANGELOG.md

@@ -37,7 +37,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
   // old code `readlink(&path, &mut buf)` can be replaced with the following
   let _: OsString = readlink(&path);
-
+  
   // old code `readlinkat(dirfd, &path, &mut buf)` can be replaced with the following
   let _: OsString = readlinkat(dirfd, &path);
   ```

src/unistd.rs

@@ -507,13 +507,13 @@ pub fn mkfifo<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()> {
 }
 
 /// Creates new fifo special file (named pipe) with path `path` and access rights `mode`.
-///
+/// 
 /// If `dirfd` has a value, then `path` is relative to directory associated with the file descriptor.
-///
+/// 
 /// If `dirfd` is `None`, then `path` is relative to the current working directory.
-///
+/// 
 /// # References
-///
+/// 
 /// [mkfifoat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mkfifoat.html).
 // mkfifoat is not implemented in OSX or android
 #[inline]